TM 9-1240-400-34&P
6
Measure distance from head assembly (4) to
mark on wall in inches (centimeters).
7
Multiply distance in step 6 by 0.30350 (tangent of
300 mils).
8
Place tape (5) (item 14, appx C), above and
below mark, at distance determined in step 7.
9
Rotate elevation knob (6) from stop-to-stop.
Reticle must follow plumbline within 0.5 mil. Line
of sight must elevate, or depress, no less than
300 mils.
10
If plumb travel is not within limits, replace prism
assembly. Refer to page 2-50.
11
If line of sight travel is not within limits, adjust
elevation knob. Refer to page 2-71.
ELEVATION MECHANISM BACKLASH
1
Aline reticles by turning elevation knob (1),
clockwise, without overtravel.
2
Check that micrometer (2) is zeroed.
3
If not, loosen three screws (3) and turn
micrometer (2) so that index points to "0".
Tighten three screws.
4
Rotate elevation knob (1), counterclockwise, at
least a half turn, and return clockwise with no
overtravel to aline index to zero.
5
If reticles are not within 5.0 mils, adjust head
assembly. Refer to page 2-57.
2-71
